The area of a triangle is (base*height)/2
Therefore: 12*10=120/2=60. Since there are three triangles then you multiply 60 by three. 60*3=180
Since the triangle in the middle is equilateral the height is 10. (10*10)/2=50
180+50=230
The answer is 230 inches²
Answer:
B. 
Step-by-step explanation:
Let l represent length of rectangle and w represent width of rectangle.
We have been given four formulas for the perimeter of rectangle. We are asked to choose the formula that displays a common student error for finding the perimeter.
We know that perimeter of a polygon is sum of all sides of the polygon. We also know that rectangle is polygon having two sets of equal sides.
The perimeter, P, of rectangle will be sum of its all sides that is:
Combine like terms:
Factor out 2:
Upon looking at our given choices, we can see that formula represented by option B displays a common student error for finding the perimeter.
Place each fraction under a common denominator. Remember, the number you multiply to the denominator must also be multiplied to the numerator
29/40 = 29/40
7/10(4/4) = 28/40
3/5(8/8) = 24/40
As seen by the fractions above, the order is 24/40, 28/40, and 29/40, <em>or</em> placed in it's original form is 3/5, 7/10, 29/40.
29/40 is the greatest, and is your answer
hope this helps
Answer:A
Step-by-step explanation:
8 is the only equal number
Let x be the number of months.
The first plan is 15 dollars sign up fee and 38 dollars per month. So the equation is 38x + 15.
The second plan is 78 dollars as sign up fee and 31 dollars per month. So the equation is 31x + 78.
We need find when x has the same value in both equations, so we do their equality:
38x + 15 = 31x + 78
Let's subtract 15 from both sides
38x + 15 = 31x + 78
38x + 15 - 15 = 31x + 78 - 15
38x = 31x + 63
Now let's subtract 31x from both sides to have the variables on a side and the numbers on side:
38x = 31x + 63
38x - 31x = 31x - 31x + 63
7x = 63
Divide both sides by 7 to have the variable x on a side and its value on the other:
(7x)/7 = 63/7
x = 9
So at month 9, the 2 plans will cost the same.
Let's check our answers, and let y be the cost:
y = 38x + 15 = 38*9 + 15 = 357
y = 31x + 78 = 31*9 + 78 = 357
Our answer has been approved.
Hope this helps! :D
